The ends of optical-fiber cables need to be connected mechanically to other apparatuses, with the optical fibers themselves being connected to optical processing devices received in said other apparatuses.
In order to avoid transmitting the forces which are exerted on the outer jacket of the cable to the fibers themselves, it is common practice to make "free-structure" cables in which the fibers are free relative to the other components of the cable.
Typically, such cables comprise a substantially cylindrical core and an outer protective jacket, the core being provided with helical grooves around its periphery with each groove freely receiving an optical fiber, and optionally being reinforced by a central strength member. A sheath of braiding may optionally be interposed between the core and the jacket.
The assembly is called a free-structure assembly since the optical fibers do not withstand the forces imparted to the mechanical components of the cable since they are freely mounted in the grooves of the core.
However, at the ends of such cables, it is particularly awkward to provide mechanical holding devices which do not interfere with the free structure.
For example, in the assembly shown in French patent application number FR 85 14765, the strength member is locked in a central end fitting and the protective jacket of the cable is clamped by two means which are distinct and interconnected to each other.
Such a solution is far from convenient to implement and its traction strength is relatively limited. The cable begins to slide at about 30 kgf, and the connection breaks at about 70 kgf.
The present invention seeks to provide good quality retention or holding of the cable up to forces of about 150 kgf to 200 kgf, while using means which are simple to implement.
U.S. Pat. No. 4 460 159 discloses a mechanical holding device for a free-structure optical-fiber cable, in which the cable comprises a substantially cylindrical core and an outer protective jacket, the core being provided with peripheral grooves in which optical fibers are freely received, and said holding device comprising a retaining block which is molded directly about the core and the protective jacket over a bared portion of each of them.